On Mon, Apr 14, 2008 at 07:47:22PM +0200, Jan Kara wrote: > Hi Josef, > > On Fri 11-04-08 14:42:58, Josef Bacik wrote: > > On Tue, Apr 08, 2008 at 02:11:49PM +0200, Jan Kara wrote: > > > Hello, > > > > > > attached is a jumbo patch that reverses locking order of transaction > > > start and page lock in ext3 and rewrites handling of ordered data mode in > > > JBD and ext3. Note that the patch will break compilation of ext4 and OCFS2. > > > The patch survives LTP run on my test machine so it shouldn't eat your data > > > immediately but bugs are of course possible... > > > I'm very interested in any results (both positive and negative) you could > > > get with it :). Thanks for testing it. > > > > > > Honza > > I just hit a problem with your patch. In journal_destroy() we do a > > iput(journal->j_inode) and then kfree the journal, so when the iput comes back > > into journal_release_jbd_inode we are doing a use after free which in my case > > resulted in a panic. I was going to fix it but I figure since this is still in > > transit you would have to just rewrite it so I'm not going to attach one, just > > giving you a heads up. Let me know if my explanation wasn't clear enough. > Thanks for letting me know. But I don't quite get it: > journal_destroy() does: > if (journal->j_inode) > iput(journal->j_inode); > if (journal->j_revoke) > journal_destroy_revoke(journal); > kfree(journal->j_wbuf); > kfree(journal); > } > > iput() will eventually call generic_forget_inode() which calls > clear_inode() in which we do journal_release_jbd_inode(). But at that > moment journal still exists to I don't see any use after free... But > possibly there could be some other inode in the inode list but which one is > it? > Hmm sorry in my pretend world iput goes off and does its thing and everything keeps going... You are right it cant be that inode, but I definitely got a panic so there must be some other inode in the inode list that is getting freed after the journal is freed. Thanks much, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
